Bicyclists break traffic laws, but they do so at a lower rate than either drivers or pedestrians. It would be safe to say that almost 100 percent of roadway users break traffic laws. Yet the general public’s perception of lawbreaking behavior by drivers and bicyclists is vastly different—at least if you listen to talk radio or read the comments section to online news stories.

This difference may be linked to the low mode share for transportation bicycling, and your personal reaction may be linked to whether you get around by bike and whether you yourself are mostly law-abiding in the same situation. In addition, bicyclists’ lawbreaking ways are rational and generally safe, whereas drivers’ most common types of illegal behaviors—speeding and running red lights—are two of the top factors in injury and fatal crashes. Red light running by motorists is so common that Google has programmed its autonomous cars to wait one second after a green signal before proceeding.

These are among the conclusions of twopapers by University of Colorado Denver professor Wesley Marshall. Marshall noted that there are few studies of the rate of bicycling lawbreaking and fewer still of why bicyclists flout the laws they do. In order to gather information about the behaviors of drivers, bicyclists, and pedestrians, the reasons for any lawbreaking behavior, and their attitudes toward other road users, he performed a scenario-based survey of 18,000 respondents. Both articles are based on the results of the survey.

In an article in the Journal of Transport and Land Use, Marshall concludes that while almost 100 percent of road users are scofflaws, regardless of mode, the reasons for lawbreaking differ. Drivers and pedestrians generally report that they are saving time. Saving time came in third as a reason for bicyclists, but personal safety was the top reason, with saving energy as second. Visibility to other road users was the fourth place answer.

All road users feel they are acting safely, and statistically they are. Even drivers who speed or run red lights have a small risk of a crash, even with decades of driving. However, if a fatal crash does happen, there is a 50 percent chance the fatality will be an innocent party. This is in contrast to the chances of an innocent-party fatality due to a scofflaw bicyclist, which is extremely rare.

The second article, in Transportation Research Part F, examines why driver lawbreaking does not seem to engender the same ire and actual aggressive behavior, i.e. road rage, as that of scofflaw bicyclists. Marshall and his co-authors attribute this difference to the number of people who bike and find that individuals who themselves bicycle for transportation are less likely to report an aggressive response. “As an individual’s own bicycling experience increases, their likelihood of an aggressive response to bicyclists in a mixed-traffic encounter is reduced.”

Finally, even when bicyclists are operating legally, their behavior may be perceived by drivers as unacceptable. Marshall finds that bicyclists are often put in a no-win situation by existing infrastructure.

Across much of the United States, bicycle-specific infrastructure is lacking, leaving those who choose to bicycle with limited physical cues as to appropriate—or lawful—behavior. On busy arterial streets, for example, a bicyclist may choose to ride on the sidewalk out of safety concerns; yet, this is illegal in many communities in the U.S. Alternately, a bicyclist in mixed-traffic may ‘‘take the lane” to avoid the door zone or being passed too closely by a following car; however, this legal behavior may be interpreted as rude or reckless by drivers.

The two papers contain a wealth of information and leave much room for additional research. Marshall gathered information about demographics, rationales, and geography of lawbreaking behavior by bicyclists. But as bicycling becomes more common and more popular for transportation, recreation, and exercise, further understanding of attitudes and safety issues would be beneficial. However, it is clear that none of us follow all the traffic laws, regardless of how we travel. We just have different reasons for our transgressions, and our different reactions to the transgressions of others are shaped by our own experiences in the same situation.